Regulator



Ml'h '37 w41 R. A. @EisELMAN REGULATOR Filed July 1G, 1958 INVENTOR WITNESSES:

Patented Mar. 18, 1941 UNITED STATES PATENT OFFICE REGULATOR Pennsylvania Application July 16, 1938, Serial No. 219,527

8 Claims.

My invention relates to regulators, and particularly to regulators of the rheostatic type such as are effective for controlling the eld excitation of dynamo electric machines.

It is an object of my invention to provide a regulator of the rheostatic type for use in controlling the excitation of dynamo electric machines which require a small amount of energy to operate and in which the rheostat controlling element is movable through a small range of travel for effecting a large correction in the regulated quantity.

It is a further object of my invention to provide a regulator in which a magnetic circuit is employed having a substantially iixed air gap, so that the force upon the armature is independent of the position of the armature within the gap, except as modified by the shape of the armature to compensate for varying mechanical resistance to the movement of the armature throughout its operating range.

Other objects and advantages of my invention will be apparent from the following description of one preferred embodiment thereof, reference being had to the accompanying drawing, in which:

Figure 1 is a diagrammatic view illustrating circuits and apparatus employed in one embodiment of the invention,

Fig. 2 is a side elevational View of the regulator illustrated in Fig. 1, and

Fig. 3 is a front elevational View.

Referring particularly to Fig. 1 of the drawing, a regulator constructed in accordance with the invention is illustrated as arranged for controlling the voltage of a generator having an armature I connected to supply current to circuit conductors 2 and 3, and having a eld winding 4 connected in shunt relation to the armature through a circuit including conductor 5, regulator resistor 6, conductor 1, generator field rheostat 8, field winding 4 and conductor 9. A rheostat controlling element is provided including a plurality of leaf springs I2 arranged in a stack and so mounted that their fixed iends are insulated from each other and connected by conductors I3 to a plurality of points along the regulator resistor 6. The other ends of the leaf spring I2 are free to move and have a biasing force toward the left, as viewed in Fig. 1, for biasing them into engagement with a stop block I4 of insulating material which limits their motion in one direction, and spaces the free ends of the spring elements I2 so as to maintain them out of contact making engagement with one another when in engagement (Cl. 20G-96) with the block I4. The several leaf springs I2 may be moved in succession from engagement with the stop block I4 with adjacent springs I2 and into contacting engagement by a driving member I5 carried on a movable arm I6 for controlling the position of the leaf springs I2 to control the effective value of the resistor 6 by short circuiting selected portions thereof. The moving arm I6 is mounted by means of horizontal springs I'I and vertical springs I8 on the magnet structure of the regulator in a manner to be later described.

The core structure provided is formed in the shape of a square Cand comprises a winding leg about which the turns of the energizing winding 22 are wound and to the opposite ends of which lateral core legs .23 and 24 are connected by means of screws 25. inwardly extending core portions 26 and 21 are attached to the outer free ends of the core legs 23 and 24 by means of screws o 28. The inner faces 29 and 30 of the members 26 and 21 are spaced to provide for receiving an armature 32 of magnetic material therebetween that is mounted on the lower end of the arm I6 by means of screws I9 and has two opposite par- 0 allel faces 33 positioned adjacent the faces 29 and 30 of the fixed core structure to provide a double air gap of substantially constant value independently of the position of the armature 32 n within its range of travel. The inner surface 34 of the armature 32 is cut away at its lower portion so that, as the armature travels between the opposite faces 29 and 30 of the fixed core structure varying widths from top to bottom of the armature 32 will be included between these surfaces for a purpose to be later explained.

The movable arm I6 carrying the armature 32 at its lower end, and the driving member I5 at its upper end, is supported by springs I1 and I8 to provide a frictionless pivot along the line of intersection of the planes of the springs I'I and I8 at 35 as shown in Fig. 3.

A supporting bracket 36 is provided attached to the core legs 23 and 24 by means of screws 3l, a portion of this bracket being shown out away in Fig. 1 to better illustrate the position of the armature 32 within the air gap. A bracket 38 is provided that is attached to the movable arm I6 by means of screws 39. The upper ends of the vertical spring members I8 are attached to the bracket 38 by means of screws 42. The outer ends of the horizontal spring members I 'I are attached to the bracket 36 by means of screws 43 and the inner ends of the springs I1 are attached to the bracket 38 by means of screws 44.

A bracket 45 is provided extending upwardly from the winding leg of the core structure on the upper end of which an adjusting screw 46 is provided to which one end of a driving or restraining spring l1 is attached, the other end being attached to a pin 43 passing through an opening in the movable arm I5. A stop 49 is provided in the upper portion of the movable arm I6 for limiting the movement of the arm, and which engages the support 52 that carries the leaf springs I2 together with their mounting assembly, which assembly is, in turn, supported on the panelboard 53 through an opening in which the leaf springs I2 extend for connection to the regulating resistor The core structure is mounted on the panel 53 by means of bolts 54 which may extend through a spacer member 55 for positioning the core structure the desired distance from the panelboard 53. The leaf sprin'g assembly for short circuiting portions of the resistor 6 may correspond with the construction more fully disclosed in a copending application of Clinton R. Hanna and Stephen Sentipal, Serial No. 203,876, led March 23, 1938, for Regulators and assigned to the same assignee as this application.

The operation of the regulator is as follows: When the generator I is started and the voltage applied between conductors 2 and 3 is below the desired value, the force of the spring 41 is more than the restraining magnetic pull on the armature 32, thus biasing the arm I6 to the right as viewed in Figs. 1 and 3, and causing the driving member i5 to hold the several leaf springs I2 out of engagement with the block I4 and in circuit closing engagement with adjacent spring members to short circuit the several portions of the regulating resistor 6. The regulator is energized through a circuit extending from conductor 2 through a conductor 56, adjustable resistor 51, conductor 58, winding 22, conductor 59, the primary winding 6I] of a stabilizing transformer to conductor 3. The winding 60 of the stabilizing transformer is inductively connected to a winding 6I that is connected across the field winding 4 of the generator, As the voltage between conductors 2 and 3 increases, the energization of the winding 22 increases and exerts a corresponding magnetic pull on the armature 32 to move it further into the air gap between the faces 29 and 30 of the core structure.

The double working air gap consisting of the two gaps between the faces 33 of the armature and the faces 29 and 30, respectively, of the core portions 2G and 21 provides a substantially constant total air gap, since the armature 32 is so mounted that its axis of movement 35 is at right angles to the armature faces 33 and the armature moves between the two parallel planes bounded by these surfaces. It will, therefore, be apparent that the armature 32 moves in a constant air gap with a varying overlap between it and the adjoining core portions 26 and 21 so that the force exerted on the armature may have a constant value for a constant voltage on the winding 22 and not vary with the position of the armature in the air gap. If the inner surface 34 of the armature 32 were continued vertically downward, instead of being cut away as shown in Fig. 3, the rate of change of flux passing through the armature would remain constant for any position of the armature, thus insuring a pull on the armature that is varied in accordance with the variation in the voltage across the winding 22.

However, as the voltage between conductors 2 and 3, and consequently the voltage applied to the winding 22, increases, the armature 32 is moved toward the right, and the driving member I5 is moved toward the left, as viewed in Figs. 1 and 3. During this movement the tension on the restraining spring i1 increases and the bias of the several leaf springs I2 against the driving member I5 decreases as successive springs I2 are brought into engagement with the stop I4, thus decreasing the total number of such springs that are biased against the driving member I5 as this member moved towards the left. The decrease in the force of the springs I2 is, however, less than the increase in the force of the spring 41. The armature 32 is so shaped by cutting away a portion thereof, as shown by the slope of the inner face 34 in Figs. l and 3, that, as the armature 32 moves further into the air gap between portions 25 and 21 cf the core structure, the width of the armature 32 from top to bottom will increase, thus causing the magnetic pull on the armature 32 to increase to compensate for the increase in the force of the spring 41. The particular slope of the face 32 is determined by the total forces of the spring l1 and the plurality of leaf spring Contact members I2 and is so determined that the sum of the spring forces in any position of the armature Within the regulating limits of travel is just counterbalanced by the magnetic pull within the same limits of travel. By so counterbalancing the spring forces by the magnetic pull on the armature 32 the position of the armature is determined solely by the degree of energization of the winding 22.

With the construction illustrated and described,y

a constant air gap is provided that does not change with changes in the position of the armature, Thus the pull on the armature for controlling the regulating resistor may be made responsive to the degree of energization of the core, Also by varying the amount of iron in the air gap with changes in the position of the armature, the varying mechanical bias with changes in position may be compensated so that the desired straight line characteristic between armature position and core energization is maintained.

Various modifications in the details of the apparatus illustrated and described within the spirit of my invention will appear to those skilled in the art, and I do not Wish to be limited otherwise than by the scope of the appended claims.

I claim as my invention:

l. In a regulator, a plurality of flexible members having portions clamped in fixed relation and insulated from one another, the corresponding outer ends of said flexible members being free to move, a movement limiting stop against which the free ends of said exible members are biased for positioning them in spaced relation, means controlled by the regulated quantity for actuating said flexible members from engagement with said stop and into circuit closing engagement with adjacent members, said means including a core structure forming a substantially closed magnetic circuit .having adjacent ends thereof spaced apart an armature for moving said flexible members mounted in said space to move about an axis eX- terior of said space to provide a substantially constant double working air gap between the opposite sides cf the armature and the ends of the core, and a winding for magnetizing said core structure energized in accordance with regulated quantity, said armature being so formed that as it moves in said substantially constant double working air gap the area between the pole faces changes in a non-linear relation to the amount of movement so that the forces caused by the flexible members in any position of the armature are counter-balanced by the magnetic pull.

2. In a regulator, a plurality of flexible contact members biased in spaced relation against a stop .means, a driving member biased by a driving spring for actuating varying numbers of said flexible members from engagement with said stop means into circuit closing engagement, means for operating said driving member against the bias of said driving spring comprising an armature, a core structure forming a substantially closed magnetic circuit having adjacent ends thereof spaced apart to receive said armature and provide a substantially constant double working air gap between opposite faces of the armature and the spaced ends of the core, the inner face of said armature being sloped backward from its innermost surface an amount such that as the armature advances between the pole faces of the electromagnet the area of the armature between the pole faces varies an amount necessary to compensate for varying spring pressure.

3. In a regulator, a plurality of flexible contact members biased in spaced relation against a stop means, a driving member biased by a driving spring for actuating varying numbers of said flexible members from engagement with said stop means into circuit closing engagement, means for operating said driving member against the bias of said driving sp-ring comprising an armature, a core structure forming a substantially closed magnetic circuit having adjacent pole faces thereof terminating in parallel flat surfaces spaced apart to receive said armature, said armature having parallel fiat surfaces adjacent the spaced pole faces of the core to form a substantially constant double Working air gap between opposite faces of the armature and the spaced pole faces of the core, the inner surface of armature being sloped at an angle to the direction of movement so that the area between the pole faces changes in a non-linear relation to the amount of movement to compensate for varying spring bias with changes in position.

4. In an electromagnet for controlling the operation of a plurality of iiexible contact members biased in spaced relation against a stop means, a driving member and Ia driving spring for actuating varying numbers of said flexible members from engagement with said stop means into circuit closing engagement, in combination, means for operating said driving member against-the bias of said driving spring comprising an armature and a core structure forming a substantially closed magnetic circuit having adjacent pole faces thereof terminating in parallel flat surfaces spaced apart to receive said armature, said armature having parallel fiat surfaces adjacent the spaced pole faces of the core to form a substantially constant double working air gap between opposite faces of the armature and the spaced pole faces of the core, the inner surface of the armature being shaped to vary the width of the armature within the air gap upon changes in the position thereof an amount that the forces due to spring bias in any position within regulating limits of travel is just counter-balanced by the magnetic pull within the same limits.

5. In a` regulator, a plurality of flexible contact members biased in spaced relation against a stop means, a driving member for actuating varying numbers of said flexible members from engagement with said stop means into circuit closing engagement, means for operating said driving member comprising a spring biasing means and an armature, a core structure forming a substantially closed magnetic circuit for varying the pull on the armature and having adjacent ends thereof terminating in parallel fiat surfaces, said armature having parallel flat surfaces adjacent the spaced ends of the core to form a substantially constant double working air gap between opposite faces of the armature and the spaced ends of the core, the parallel surfaces of said armature extending radially from the axis of movement of the armature, the inner surface of the armature being curved to provide a varying Width of armature Within the air gap to compensate for varying spring bias with position.

6. In an electromagnet for controlling the operation of a plurality of flexible contact members biased in spaced relation against a stop means, a driving member for actuating varying numbers of said flexible members from engagement with said stop means into circuit closing engagement, and a restraining spring for biasing said driving member in one direction, in combinaton, an armature for opposng the bias of the restraining spring, a core structure forming a substantially closed magnetic circuit for varying the pull on the armature and having adjacent pole faces thereof terminating in parallel fiat surfaces spaced apart to receive said armature, said armature having parallel flat surfaces adjacent the spaced pole faces of the core to form a substantially constant double working air gap between opposite faces of the armature and the spaced pole faces of the core, said armature being mounted to move in said air gap in a space bounded by the parallel pole faces, the inner face of the armature being shaped to vary the width of the armature within the air gap upon changes in the position thereof to provide an increasing force with change in position in one direction an amount such that the forces due to spring bias in any position within regulating limits of travel is just counterbalanced by the magnetic pull within the same limits.

7. In a regulator, a plurality of flexible circuit controlling members having portions clamped in fixed relation, said fixed portions being insulated from one another, the corresponding outer ends of said flexible members being free to move, a movement limiting stop against which the free ends of said flexible members are biased for positioning them in spaced relation, a driving member for actuating said flexible members from engagement with said stop and into engagement with adjacent members, Ia core structure forming a substantially closed magnetic circuit having adjacent ends thereof spaced apart, an armature operatively connected to said driving member and mounted in said space to provide a substantially constant double working air gap between the opposite sides of the armature and the ends of the core, and a Winding energized in accordance with a. regulated quantity for magnetizing said core structure, said armature having a variable width so dimensioned that, as it moves in said substantially constant double working air gap the changing forces caused by the flexible members are compensated by a changing magnetic pull, so that in any position of the armature the forces of the flexible members are counterbalanced by the magnetic pull.

8. In a regulator, a stop member, a plurality of flexible contact members biased against said stop member to be held in spaced relation thereby, a driving member biased by a driving spring for actuating varying numbers -of lsaid. exible members from engagement with said stop member `into circuit closing engagement, means for operating said driving member against the bias y of said driving spring comprising an armature, a

core structure forming a substantially closed magnetic circuit having adjacent ends thereof spaced apart to receive said armature and provide a substantially constant double working air gap be- 

